Years before the time of Christ, humans chased after deer and bighorn sheep through the trees along the Santa Cruz River. What is to become of the site of Tucson's birth?

A model provides a virtual reconstruction of the San Agustn chapel, or Convento, an 18th-century structure built on the banks of the Santa Cruz River in what is now Tucson.

Tucsonans in possession of Convento photos should call Doug Gann at 882-6946. For a view of his virtual reality work, check out www.cdarc.org. For tours of the archaeology site, call Desert Archaeology at 881-2244. Margaret Regan has won two journalism awards from the Arizona Press Club for her reporting on Rio Nuevo. See Tucson Weekly, May 9, 2001, for her prizewinning account of how Tucson lost the Santa Cruz River.

It was only nine o'clock on this blazing June morning, but already the sun was beating down on the dusty Rio Nuevo acres west of downtown.

A backhoe was chugging past the big dirt piles at the archaeology site along the parched Santa Cruz River, and in this dry-bone year the whining machine kicked up great clouds of dust wherever it went. A radio tinkled under a spreading tamarisk, the plot's lone tree; nearby, clusters of sweaty archaeologists crouched in the shade underneath cloth ramadas held up by poles.

All of the workers were on their knees, wielding tiny trowels as they carefully scraped the mud-plaster floors of ancient pithouses. The houses' circular foundations, 8 feet across and 2 feet deep, are the remains of a village that thrived in the shadow of A Mountain 2,500 years ago.

Under one of the makeshift tents, a couple of the "dig bums"-young archaeologists who sign up for jobs on contract, going from dig to dig-were having a good morning. Outfitted in the quintessential dig bum uniform of work boots, long pants and shirt, and neckerchief beneath a baseball cap, they'd been out on the site only three hours. Yet they'd already they'd turned up a couple of priceless treasures.

Avi Buckles proudly pointed to a metate in the dirt.

"We found it right there," he boasted. "I found it this morning."

The smooth stone slab still lay on the floor of the pithouse where it had been left behind two and a half millennia ago. Some early resident of this once-fertile floodplain used it to grind out her corn, smoothing down those kernels just a few years before the Greek philosopher Aristotle was born, and long centuries before the Romans embarked on their empire.

Not to be outdone by the metate, Buckles's pitmate, Allen Denoyer, shouted out a discovery of his own, one interesting enough to lure a small clutch of admiring archaeologists away from their own pithouses. He picked up a dusty red projectile point and cradled it in his hand. Archaeologists know better than to call such things arrowheads, but still, the stone tool-made of glittering red chert-was a "hunting weapon," Denoyer explained, as he threw a colorful flag dart to the ground to mark the point of excavation. "It was attached to a short stick."

That meant that long years before the time of Christ somebody was chasing after deer and bighorn sheep through the trees along the river, right here in the birthplace of Tucson.

Denoyer, Buckles and the rest of their nine-person archaeology team were in the pits on this 105-degree day courtesy of Tucson's taxpayers. The Rio Nuevo project, the public-private bonanza that could end up pouring $750 million dollars plus into Tucson's dispirited downtown, awarded Desert Archaeology a $2 million contract a year and a half ago. Ever since, the local firm has been excavating the ancient flood plain at the base of A Mountain's eastern slope, in search of the succession of residents who prospered in this lush desert oasis.

Tucsonans before the word was coined, these people range from the farmers who grew corn here in ancient times, on through the Hohokam of a thousand years ago, all the way up to the 18th century Pima Indians and Spanish friars and the 19th century Mexicans and Anglos. Chinese immigrants were the last farmers in this multi-millennia agricultural cast to garden here; they turned Tucson's diet toward fruit and vegetables a hundred years ago, just before American entrepreneurs killed the river. (This fall, the archaeologists will bring their shovels to a downtown parking lot believed to be above a corner of the city's 18th century Spanish presidio.)

So far, the results of their labors have been mixed. The crew's search for the late, lamented Convento has been almost a total bust. Built for Spanish missionaries around 1800 and scavenged by Tucsonans in the latter 19th century, the city ignominiously bulldozed what was left of it in the late 1950s to make way for a landfill.

"There's nothing left of the Convento or (San Agustín) chapel," Desert Archaeology team boss Jonathan Mabry said bluntly.

"We found a handful of rocks," his colleague J. Homer Thiel told a dismayed audience at a May forum in the Temple of Art and Music. "We dug trenches at the Convento and chapel, but it was thoroughly bulldozed."

The most interesting finds in the trash heap that occupies the sacred Convento ground were well-preserved 1950s artifacts. In an exquisite irony, Thiel noted, "We found a phone book from 1958 and looked up the number of Julian Hayden, a prominent archaeologist."

The Rio Nuevo plan, endorsed by the voters in 1999, envisioned a re-creation of the Convento based on the hoped-for archaeology. Supporters of reconstruction argue that the Convento was amply recorded in photographs, and a young archaeology grad student, Doug Gann, has been using the photos and computer wizardry to create a realistic virtual model. Still, the total obliteration of the building's foundation gives new ammunition to critics who already disapprove in principle of rebuilding a lost historic structure.

That debate may intensify in the next year. On July 1 the City Council is expected to approve a request for proposals by design teams eager to plan the future archaeology and history park. The winning group will pick up $500,000 to blueprint ways to honor the lost mission and the long-ago Indian settlements, and soon. Rio Nuevo project director John Jones expects to begin construction on the park and the new Convento in a year's time and "have it open in 2004."

PARTIALLY MAKING UP for the Convento archaeological fiasco are the spectacular prehistoric finds.

As Marty McCune, the city's historic program administrator, put it in a memo: Counterbalancing the low point of finding "no evidence of the Convento foundations" is the giddy high of "finding a 4,000-year-old Early Agricultural settlement."

The archaeologists have found a settlement so ancient that it makes the recently unearthed metate and red projectile point mere babies at 2,500 years old.

"This is one of the most significant findings of the Rio Nuevo project," said Mabry, who as team boss is on site each workday. On the northwest side of the site, near Congress Street, "we found a pithouse settlement dating back to 4,000 years ago. We found pottery and ceramic figurines and corn. We didn't know people were living in pithouse villages then or making pottery. This is among the oldest corn found in the Southwest. And this is the oldest pottery we've found in the Southwest."

To make his point, Mabry picked up a 4,000-year-old potsherd as he sat in the shelter of the site's big mesquite. The pink-gray color of the fragment, apparently a piece of a cup, exactly matched the tones of the earth beneath his feet. It bore no paint decorations, but around its rim some ancient artist had etched a simple design with a thumbnail. Radiocarbon dating shows that these First Farmers, as Mabry informally calls them, were slapping out clay works on their fertile riverbank a couple of hundred years before Hammurabi cranked out his Code in the Fertile Crescent, half a world away.

Even more exciting, to students of engineering, is the intricate network of irrigation canals dating from 2,500 years ago. Scholars long believed that the earliest Arizona canals were in the Phoenix Basin, but the newly discovered Rio Nuevo canals predate those by 500 years. The outlines of the ancient canals are visible on the sides of trenches the team cut into the ground. They're like paintings in the soil: a semicircle of dark brown dirt at bottom, a semicircle of pale ochre silt at top.

"Until these discoveries it was a big mystery where the Hohokam learned to build canals, " Mabry said. The people of the Santa Cruz Valley invented irrigation agriculture for themselves, and the Hohokam who came along about 1,000 years ago just followed their example.

"What we have here is a 2,500-year sequence of canals," Mabry said. "This was a lush oasis for farmers for two-and-a-half millennia until 100 years ago. This is why Tucson is here."

The similarities in the pottery and architecture of the 4,000-year-old and 2,500-year-old First Farmers, Mabry said, are dramatic evidence of "cultural continuity between 4,000 years ago and 2,000 years ago." The 2,500-year-old site shows signs of being a real village. A canal bisects the settlement of 25 pithouses, and nine of the houses are grouped in a semi-circle around a rudimentary plaza, in front of a Big House. The communal effort expended on the Big House, as well as the organized labor required by the elaborate canals, Mabry said, argue for the first real village society in the Southwest.

"We have the first irrigation in the Southwest, the first pottery in the Southwest, and the first villages in the Southwest," he said. "It's pretty exciting that it's all right here in Tucson."

These extraordinary discoveries give new impetus to archaeologists who have been arguing for some time that Tucson could be one of the oldest hometowns in America. Just a generation ago, in the 1960s, respected archaeologist Emil Haury promulgated the scholarly standard that people had lived here about 2,300 years, from around 300 BC. But in the last decade, archaeologists have been constantly pushing that date farther back in time. Their digs are a happy result of a state law that requires archaeology on public construction projects; every time Interstate 10 is widened they get the chance to burrow into the nearby Santa Cruz riverbanks, Tucson's archaeological "hot zone." What they found-15 settlements along the Santa Cruz every few miles from Tangerine Road to San Xavier--had until now pushed the date for human habitation along the Santa Cruz to about 3,000 years ago, 3,500 years at the most. Now that's changed.

Mabry may be equipped with a Ph.D. from the UA's respected anthropology program, but he still wears the dig bum's work boots and baseball cap. And he still has the dig bum's swagger. The 4,000-year-old discoveries, he declared unequivocally, make "Tucson the oldest continuously inhabited place in the United States."

Mabry's boss, Bill Doelle, head of Desert Archaeology, showed up at the site in the searing heat of noon hatless and in a dress shirt, fresh from a city meeting. He's more buttoned-down than Mabry--and more circumspect.

The claim of "longest" and "continuous" is "relatively accurate," Doelle conceded. "It's clear these folks are some of the earliest farmers in the Southwest.... But these 4,000-year-old folks were probably still fairly mobile. It was not a city. But even if they went away (periodically) people kept coming back, because of the water and because A Mountain presented a high point to look from-for attackers or to look at the sky."

But if Doelle won't hop on the "longest continuous" bandwagon, he is willing to go with a technical term that is surprisingly poetic.

WHAT IS TO BECOME of that persistent place may shape up to be a persistent headache for Rio Nuevo planners.

The voters approved a tidy $10 million to build the archaeological and historical park along the banks of the Santa Cruz. (An additional $2 million is designated for the Presidio.) The northern end of the Rio Nuevo plot is to host a complex of museums, shops and restaurants, which may unfortunately obliterate the ancient First Farmers sites, but the southern end is to celebrate the riverbank's long sweep of history.

The question is: whose history and how?

"It's a huge challenge to interpret 4,000 years of history," McCune, the city historic program administrator, acknowledged. "Williamsburg (Va.) just covers 20 to 50 years. We have to figure out how we're going to interpret it."

Some things are not too problematic. The prehistoric archaeological excavations, after yielding up their data and artifacts, will be covered over-in fact the 4,000-year-old site is already back under the soil. Museum builders, with the help of the archaeologists, could leave some intact within a museum's rooms. A Hohokam village, with its pithouses of pole and thatch, could be periodically constructed and burned, to yield "new" archaeology for teaching kids. The walled Mission Gardens to the west, full of canals and Hohokam pot sherds, are in good shape. They likely will be operated as a historic demonstration garden. Some water may be returned to the dessicated river, and its riverbank mesquites and cottonwoods restored.

Most vexing is what to do about the old Spanish mission. Ironically, though it's one of the more recent settlements along the Santa Cruz, 20th-century Anglos destroyed it far more thoroughly than they did the much older sites.

Mission San Agustín had a relatively brief hour on the floodplain stage. Around 1770 Spanish friars created a mission "visita" for visiting priests attending to the Pima living there in a river village. But the Convento, a priests' residence, and its accompanying church (probably the second one on the site) weren't built until about 1800. The walled complex also had a granary and a pair of cemeteries. But the Spanish gave way to the Mexicans in 1821, and the Mexicans to the Americans in 1854. A painting from 1852 captures the Convento intact. By the time the famous photographer Carleton Watkins came along in 1880 and photographed the scene from A Mountain, the church had disappeared and the Convento was deteriorating.

Photographs of Tucsonans picnicking in the ruins chart the Convento's slow decline over the next 70 years. By the early 1950s, its adobe bricks beaten down by sun and rain, and scavenged by the citizenry, an Arizona Daily Star article reported that the old mission church "is hard to locate because so few traces of it remain."

To make things even more complicated for 21st century archaeologists, Tucson Pressed Brick Company was busily digging up clay in the mission compound from the late 19th century to the 1960s--drawing on the same clay deposits the First Farmers prized for their figurines. Their bricks built much of Tucson, including the new University of Arizona. By the middle of the 20th century, the city was searching for a nice big hole for a new landfill. City fathers seized upon the idea of throwing the town's trash into the brickyards' "borrow pits"--and into a new hole to be dug at the now-barren Convento site.

A few people cared about the impending loss of a historic treasure. Some archaeologists had been poking around since the late 1940s and McCune said that in 1956, "three minutes before the bulldozers," an archaeologist named William Wasley hastily did some salvage archaeology.

"He didn't have the best conditions, or enough money, and his workers were convicts," archaeologist Thiel said. More to the point, Wasley's interests didn't coincide with current ones. He was a physical anthropologist, more enamored of old bones than buildings. Gann, who's making the Convento computer models, believes Wasley's map of the Convento interior was wrong.

In any case, the impatient city leaders soon unleashed the earth movers, and forever obliterated the Convento's archaeological remains.

"The mentality," as McCune put it in a fine understatement, "was different then."

Though the building has vanished without a trace, the request for proposals that City Council and mayor are to vote on July 1 asks the successful bidder to look at different ways of interpreting this persistent place, "including reconstruction of buildings which no longer exist."

The idea of reconstruction has strong political support. Councilman Steve Leal, who helped stop a misguided highway that would have paved over the mission site back in the 1980s, has been an enthusiastic proponent. He hopes to enlist schoolchildren to craft the necessary adobe bricks. Not only will a new Convento and Indian village celebrate Tucson's Hispanic and Native American heritage, he wrote in a letter to the Arizona Daily Star, but it will "garner significant and recurring income from heritage tourism." His letter was co-signed by assorted Tucson bigwigs, including Cele Peterson, Dorothy Finley, Esther Tang and Alva Torres.

Bob Rodriguez, a resident of nearby Menlo Park, echoed many of his neighbors when he said that the project would "have the city give some respect to this area of the city. I'm all for reconstruction and having the kids be part of it."

John Jones, project director for Rio Nuevo, said the bottom line is that the voters approved an "interpretive and reconstruction plan" when they gave the nod to Rio Nuevo.

"We're going to do it," he said. "We will rebuild."

Nevertheless, the city's McCune is abundantly aware that many historic preservationists oppose rebuilding lost structures, and not only because it's the most expensive way to interpret an old place. Though she herself supports a careful reconstruction, she says that the opponents have "a very legitimate point of view. In the preservation community, reconstruction is always controversial." A 21st century Convento, for instance, would never be eligible to be listed on the National Register of Historic Places, she said, though the site as a whole might quality.

Jim Garrison, the state's historic preservation officer, noted dryly that he has no jurisdiction in the matter of Rio Nuevo. The reason is simple: There are no old buildings to preserve. "We're not dealing with a historic property. I'm out of the picture. Everything is new. There's nothing to be managed."

Given the politics of historic preservation dollars, some local preservationists won't voice publicly their belief that reconstruction would be a fiasco. (One sassily termed the project the "Invento.") But a couple of professionals with impeccable credentials have outspokenly opposed it, using what to historic preservationists are fightin' words: "counterfeit," "fake" and, worst of all, the dreaded "Disney."

"I'm absolutely against reconstruction of the Convento and the Presidio," said Bob Vint, the architect who has overseen restoration of the exterior of the prized Mission San Xavier del Bac. "This is like printing counterfeit money."

Other cities have come up with ingenious solutions to the problem of lost buildings, Vint said. Philadelphia, for instance, has been widely acclaimed for the way it evoked Benjamin Franklin's demolished house. Instead of building a fake new Franklin homestead, the much-admired architect Robert Venturi designed a "ghost house." Its open-air steel beams outline the walls and footprint of the original. Visitors talk of getting an eerie sense of the vanished past in the structure, and they would never mistake it for a red brick colonial.

Vint said that visitors to Colonial Williamsburg, which is full of reconstructions, are chronically misled about its authenticity.

"That's what will happen here," he said. "They'll think it's real and then they'll feel robbed and cheated. We do have an authentic 18th-century Spanish colonial building (San Xavier). It's all intact and it's original. When you have an original, why build a fake?"

R. Brooks Jeffery heads up the historic preservation program in the UA's School of Architecture, and with Anne M. Nequette he recently published the critically acclaimed Guide to Tucson Architecture. Like Vint, Jeffery said that "We all agree that the site needs to be honored" but he believes that a reconstruction dishonors the past.

"A false sense of history will be created if the San Agustín Mission is recreated," he wrote in the publication Archaeology Southwest. The desolate old mission grounds would become a "pseudo-place." "Rebuilding the Convento, in the context of the contemporary tourist-oriented development of Rio Nuevo, would serve more as a Disneyland-esque stage prop."

THE ARCHAEOLOGISTS WHO have spent a year and a half sweating on site to extract every possible piece of evidence from this sacred ground understandably are in favor of using that information to build.

On a sizzling afternoon out in the Mission Gardens, archaeologist Thiel pointed out everything from wall foundations and 1950s trash--including a painted leprechaun on a Shamrock milk bottle sherd--to ancient canals and delicate Hohokam pot fragments painted in black designs. "We found more than 100 features in the Mission Gardens," he said proudly, "stuff from the Early Ceramic cultures, the Hohokam, the Mission."

Taking refuge in his air-conditioned car to view the Mission complex proper, he acknowledged that the Convento is gone with the wind. The desire to find something, anything, was so great, he said, that "we dug a trench 25 feet deep, and went back three times." The excavation put to rest an old rumor that a city official, Tom Price, had secretly protected the foundations with a sheltering layer of sand. Not true.

Nevertheless, Thiel argued, "a large portion (of the mission complex) is still intact. We have 20 percent that's left," including foundations of the granary and walls, and even a graveyard of "Christianized Indians," which will be left undisturbed. (The Spanish friars' graves, in a separate cemetery, disappeared along with their church and residence.) He believes the compound can be re-created accurately and sensitively with the existing evidence, and labeled appropriately as a reconstruction.

"I'm a neighborhood resident," Thiel said. "One of the reasons I voted for it (Rio Nuevo) is there's no other place than San Xavier you can see the Spanish period. No place at all for the Native American story."

Gann hopes his high-tech solution will settle the argument. While the research is complex, his MO is simple. Input every available photo of the Convento into the computer software. Let the computer crunch the info. Look in astonishment at the animated model of the three-dimensional building on the computer screen. At the public forum last May, Gann's computer imagery was the star of the show. Members of the audience, who got a virtual tour via a big-screen projection, felt like they were walking through the old adobe building, climbing the stairs and gazing out the second-floor arches at A Mountain overhead.

"The first model was really crude," Gann said, but each time a photo comes in he refines the image. He's still begging the public to search every cranny for ancestral photos, and Thiel even found a postcard picturing the Convento on eBay.

"It's all started coming together," Gann said. "I now have 80 percent of the structure documented."

During his training, Gann has seen really bad reconstruction--such as a fort in upstate New York whose rebuilders mistakenly put the floor's red tiles on the roof and the foundation's stone on the walls--but he thinks Tucson can do the job right. The virtual model, he said, allows for a "a creative solution that can be historically faithful and not dishonest."

Gann understands the arguments against reconstruction, and realizes that in some ways his work has strengthened them. Jeffery, for instance, said, "What Doug has done is precedent-setting. But when we have the virtual model do we need to build the whole thing?"

Such arguments make Leal apoplectic. His letter accused reconstruction opponents of trying "to undermine both the significant commitment and opportunity that the mayor and Council have made to all of Tucson, but in particular the Native American and Hispanic communities."

The persistent argument may well deprive the persistent place of peace. But it has a historical precedent in Tucson's contentious past. Despite its riches in water, fertile soil and wildlife, archaeologist Jonathan Mabry said his team has found evidence of discord in the idyllic ancient riverbank. One of the Tucsonans of 2,500 years ago, Mabry said, unkindly hurled a dart into somebody else's back.